| VSIG4 (V-set and Ig domain-containing protein 4, also Z39Ig) is a 45-50kD macrophage-specific protein that belongs to the B7 family of molecules. Its constitutive expression depresses unwarranted T cell activation. Human VSIG4 is 399 amino acids (aa) in length. It is a type I transmembrane (TM) glycoprotein that contains a 264 aa extracellular domain (ECD) (aa 20-283) and a 95 aa cytoplasmic region. The ECD contains one V-type (aa 21-131) and one C2-type Ig-like domain (aa 143-226). Mouse VSIG4 has no C2-type domain. Over aa 20-139, human VSIG4 is 82% aa identical to mouse VSIG4. Multiple splice forms exist in human that impact the ECD and TM segments. One isoform deletes aa 67-143, while two additional isoforms substitute two aas for aa 138-233. Two new isoforms remove all or part of the TM region. Applications: Suitable for use in Direct ELISA and Western Blot. Other applications not tested. Recommended Dilution: Direct ELISA: 0.5-1ug/mL detection limit for rhVSIG4 ~ 1ng/well Western Blot: 0.1-0.2ug/mL detection limit for rhVSIG4 ~ 1ng/lane under non-reducing and reducing conditions. Optimal dilutions to be determined by the researcher. Storage and Stability: Lyophilized powder may be stored at 4C for short-term only. Reconstitute to nominal volume by adding sterile 40-50% glycerol and store at -20C. Reconstituted product is stable for 12 months at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer. |
